1. Field of the Invention
The present invention relates to a printed circuit board and a method of manufacturing the same.
2. Description of the Background Art
Flexible printed circuit boards are used in various types of electronic equipment. For example, conductor traces are formed on a base insulating layer, and a cover insulating layer is formed on the base insulating layer to cover the conductor traces in a general flexible printed circuit board. Various elements or electronic circuits are mounted on the flexible printed circuit board. Examples of the elements include photoelectric conversion elements (solar cell), light emitting diodes and so on. Light incident from the outside must be efficiently converted into electricity in order to improve conversion efficiency of the photoelectric conversion element. Light generated in the inside must be efficiently taken out to the outside in order to improve light emitting efficiency of the light emitting diode.
Providing a reflecting layer or a scattering layer in the photoelectric conversion element (see JP 2000-348784 A) and providing a light scattering/reflecting layer in the photoelectric conversion element (see JP 2005-158379 A), for example, have been proposed in order to improve the conversion efficiency of the photoelectric conversion element.
Moreover, providing a reflector to which inorganic fillers are added has been proposed in order to improve light emission efficiency of the light emitting diode (see JP 2007-218980 A).
However, providing the reflecting layer, the scattering layer or the light scattering/reflecting layer in the photoelectric conversion element increases the number of manufacturing steps. This leads to an increase in manufacturing cost of the photoelectric conversion element. Also, providing the reflector in the light emitting diode increases the manufacturing cost. Therefore, it is desired to improve the efficiency of the element without increasing the manufacturing cost of the element. Alternatively, the improved efficiency of the element attributed to its configuration is desired to be further improved.